The reproductive traits of Holstein heifer in Shahrekord

In this study 700 records from 501 Holstein heifers (born during 2006-2012) were used to investigate of reproductive performance. The linear model was employed for Analysis of Age at First Services (AFS), Age at First Calving (AFC) and Interval from First to Last services (IFL) and the Generalized Linear Model for Conception Rate (CR). Results showed that the herd on CR was significant but the difference of other traits were not significant among herds. Conception rate least square means were not significant among different seasons and service numbers. Season of birth had significant effect on AFC so that heifers born during winter had lower AFC than summer born heifers. Comparison of lest square means for reproductive parameters in the studied herds with optimum levels showed that the AFS, AFC and IFL in most herds were higher than optimum (p